Improving the Quality of Cancer Clinical Trials Workshop Summary (2008) / Chapter Skim
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Molecular Imaging
Molecular Imaging
Pages 40-48
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From page 40... ...
These speakers gave several promising examples of such molecular imaging biomarkers, and showed how they can be used throughout the drug development process. Also addressed in this session were current challenges involved with molecular imaging, suggestions for how to meet those challenges, and a discussion of how the current or potential pitfalls of molecular imaging compare to those of standard imaging.
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From page 41... ...
He added that dynamic contrast MRI, by showing changes in blood volume and blood flow into tissues over time, is useful for detecting the abnormal proliferation and leaking blood vessels that typify malignancies. Farther in the future is the possibility of researchers using hyperpolarized carbon-13 as a radioactive label for tracers that can improve the sensitivity of MRI and enable the detection of specific metabolic pathways, as opposed to the heightened overall metabolism that is seen in PET with FDG.
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From page 42... ...
2006. Quantitative fluoroestradiol positron emission tomography imaging predicts response to endocrine treatment in breast cancer.
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From page 43... ...
Piwnica-Worms' studies, a luciferase reporter gene was used to reveal tumor production of a key protein targeted by an experimental drug. Repetitive optical imaging essentially provided "a real-time in vivo Western blot of protein content over time" that gave enough pharmacodynamic and pharmacokinetic data to determine an appropriate dosing regimen for a subsequent clinical trial, he said.
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From page 44... ...
Gore showed a slide of animals treated with a drug that targets the epidermal growth factor receptor, which has been linked to several solid tumors. Optical imaging revealed that the EGF receptor density was reduced by the treatment and apoptosis was increased, as indicated by an imaging probe for annexin V
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T T 2.0 1.5 T T 1.0 N O 0.5 Treated Untreated Treated Untreated FIGURE 12 Optical imaging of animals treated with a drug that targets the epidermal growth factor receptor (EGFR) , which has been linked to several solid tumors.
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From page 46... ...
. A lack of standardization of image acquisition guidelines in clinical trials in regard to whether MRI or CT is used, the timing of contrast administration, and image slice thickness also can create discrepancies in the assessment of tumor response.
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From page 47... ...
Dr. Schwartz optimistically summed up the discussion of the challenges involved in molecular imaging by saying, "We in imaging view many of these as challenges that are readily achievable by obtaining appropriate image acquisition guidelines which could be standardized in a rational manner." One additional challenge mentioned by Dr.
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From page 48... ...
Panel member Dr. Jeff Evelhoch of Amgen agreed that "that is probably the biggest challenge that we have in using imaging in clinical trials," and that this challenge varies with the imaging modality.
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